feeding: fishes as predators feeding & predation cycles adaptations of predators

Feeding:Fishes as predators

Feeding & Predation cyclesAdaptations of predators

Predator – Prey arms race

• Co-evolution of predatory and escape mechanisms– Morphological adaptations– Behavioral adaptations– Ecological adaptations

“there is no perfect predatory nor perfect escape tactic”

Predation Cycle

• Search• Pursuit• Attack• Capture (Feeding Cycle)• Handling of Prey (Feeding

Cycle)

Feeding Cycle

• Biting• Sucking • Chewing• Swallowing

Search• Active Search (Use of locomotion while

employing senses to detect prey)

- Vision (Water column predators)• Herring & Anchovies • Tunas & Billfishes • Nocturnal Plankton feeders

Search• Active Search (Use of locomotion while

employing senses to detect prey)

- Vision (Water column predators)• Herring & Anchovies Tunas & Billfishes • Nocturnal Plankton feeders

– Olfaction• Elasmobranchs• Moray eels

Search• Active Search (Use of locomotion while

employing senses to detect prey)

- Vision (Water column predators)• Herring & Anchovies Tunas & Billfishes • Nocturnal Plankton feeders

– Olfaction• Elasmobranchs• Moray eels

– Hearing• Elasmobranchs (low frecuency sounds 20-300

Hz)

Search• Active Search (Use of locomotion while

employing senses to detect prey)

- Taste / Touch (benthic feeders)• Barbels (Catfishes, Goatfish, Croakers, etc…)• Modified fin rays (Sea robins, etc…)

Search• Active Search (Use of locomotion while

employing senses to detect prey)

- Taste / Touch (benthic feeders)• Barbels (Catfishes, Goatfish, Croakers, etc…)• Modified fin rays (Sea robins, etc…)

– Electroreception• Passive (Elasmobranchs)• Active (Elephantfish, Gimnotids, etc…)

Search• Active Search (Use of locomotion while

employing senses to detect prey)

- Taste / Touch (benthic feeders)• Barbels (Catfishes, Goatfish, Croakers, etc…)• Modified fin rays (Sea robins, etc…)

– Electroreception• Passive (Elasmobranchs)• Active (Elephantfish, Gimnotids, etc…)

Speculation Search (‘try and see’ chicken tactic…)

• usually occurs with attendant species

Search• Passive Search – Camouflage

Predators (No use of locomotion)

- Benthic Stalkers (Flounders, Scorpionfish, etc…)

•Vision•Electrorecepcion

Search• Passive Search – Camouflage

Predators (No use of locomotion)

- Benthic Stalkers (Flounders, Scorpionfish, etc…)

•Vision•Electrorecepcion

– Open Water Stalkers (gars, pike, trumpetfish)

•Vision

Pursuit• High Speed chases

- Specific to capture fast prey•Open Water – Speed

– Lamnid sharks, Tuna, Marlin…

•Benthic – Fast Braking and turning– Salmon, Striped Bass, Groupers…

Pursuit• High Speed Chases

- Specific to capture fast prey•Open Water – Speed

– Lamnid sharks, Tuna, Marlin…

•Benthic – Fast Braking and turning– Salmon, Striped Bass, Groupers…

• Fast Start Interception– Convergent evolution of body shape

– Pike, Barracuda, Gars, Needlefish…

Pursuit• High Speed chases

- Specific to capture fast prey•Open Water – Speed

– Lamnid sharks, Tuna, Marlin…•Benthic – Fast Braking and turning

– Salmon, Striped Bass, Groupers…

• Fast Start Performance– Convergent evolution of body shape

– Pike, Barracuda, Gars, Needlefish…

• Luring – Lophiiformes (fin rays), stargazers (buccal lures),

Haplochromis livingstoni (death feigning)...

Attack, Capture & Handling

• Directly related to jaw development

• Feeding Cycle (Biting, Sucking, Chewing, Swallowing)

• Mouth Positioning– Superior– Terminal– Inferior

Attack, Capture & Handling

• Directly related to jaw development

• Feeding Cycle (Biting, Sucking, Chewing, Swallowing)

• Mouth Positioning– Superior– Terminal– Inferior

• Suction Feeding (Jaw Protrusion)– Premaxillae, Maxillae & Lower Mandible– Preparation, Expansion, Compression, Recovery

• Pharyngeal Jaw– Handling / Chewing & Swallowing

Extreme Jaw Protrusion65% Head Length

Attack, Capture & Handling

• Overtake or Interception of prey• Suction of Prey

– Fastest movements if mobile prey (example: Frogfish expand mouth 14-fold in 6

milliseconds)– Slower movement if prey with limited

movement

Attack, Capture & Handling

• Overtake or Interception of prey• Suction of Prey

– Fastest movements if mobile prey (example: Frogfish expand mouth 14-fold in 6

milliseconds)– Slower movement if prey with limited

movement

• Filtering of prey– Swim with open mouths, filter planktonic prey

Filtering of Prey

CetorhinidaeBasking sharkCetorhinus maximus

Filtering of Prey

Attack, Capture & Handling

• Overtake or Interception of prey• Suction of Prey

– Fastest movements if mobile prey (example: Frogfish expand mouth 14-fold in 6

milliseconds)– Slower movement if prey with limited

movement

• Filtering of prey– Swim with open mouths, filter planktonic prey

• Prey Immobilization– Marlin, swordfish, sawfish (upper jaw extension)– Thresher Shark (tail)– Torpedo Rays (Electrical discharge)– Hammerhead Shark (head)